One of the causes of failure or complication with shoulder arthroplasty is connected with poor attachment of the glenoid prosthetic body to the glenoid cavity. When the glenoid cavity of a patient undergoing surgery is worn and/or has an impaired bony makeup, the surgeon has difficulty firstly in correctly positioning the glenoid prosthetic body in relation to the glenoid cavity, so as to give the joint face of this component a retroversion angle that is identical to, or at the very least, is as close as possible to, the anatomical retroversion of the original glenoid cavity of the patient and secondly in firmly attaching the prosthetic body to the glenoid cavity, to ensure that the attachment is sufficiently strong. An attachment that is ill-positioned and/or not strong enough leads to wear and/or detachment of the glenoid prosthetic body.
This being the case, U.S. Pat. Nos. 5,800,551 and 5,593,448, and U.S. Application Publication 2003/0055507 propose equipping the opposite face of the glenoid joint component to the joint face thereof with several projecting pegs designed to be driven into spongy bony matter with which the glenoid fossa of a patient undergoing surgery is filled. If appropriate, the glenoid fossa is filled to such a point that one or some of the pegs press via their free end against the closed end of the cortical bony vault of the glenoid cavity. In practice, positioning these pegs in relation to the glenoid cavity remains tricky when the glenoid cavity is worn. Further, inasmuch as the transmission of load between the free end of the pegs and the glenoid cavity is necessarily limited, there is a need to ensure that the periphery of the glenoid joint component is positioned resting against the end edge, that faces towards the humerus, of the vault of the glenoid cavity which procedure, in the long term, weakens this end edge by creating rims and causes the glenoid joint component to become detached.
EP 1 639 967 for its part considers providing the opposite face of the glenoid joint component to its joint face with a solid projecting anchor, in the overall form of a cone frustum, to rest laterally against the wall of the vault of the glenoid cavity, occupying the entire internal volume of the glenoid fossa. This solution prevents any bone regrowth in the fossa and soon leads to necrosis of the glenoid cavity, especially when, as before, the periphery of the glenoid joint component is designed to rest against the end border of the vault of the glenoid cavity.